Last week, I laid out the specter of tens of trillions of dollars in unfunded liabilities that we face as a nation as the baby boomers retire. This week, to continue the theme of confronting economic realities, I ask you to join me in considering the real cost of the Iraq war.

It was only four years ago when Lawrence Lindsey, then-head of the White House's National Economic Council, estimated that the "upper bound" of the cost of going to war with Iraq would be between $100-billion and $200-billion.

The massive size of that estimate scandalized the Bush administration. Up until then, the Pentagon had been privately telling Congress to expect a cost of about $50-billion.

By February 2003, just weeks before the invasion, the numbers coming out of the Defense Department had grown to between $60-billion and $95-billion. But even then, Paul Wolfowitz, the deputy secretary of defense at the time, was telling Congress that the upper range was too high and that Iraq's oil wealth would offset some of the cost. "To assume we're going to pay for it all is just wrong," Wolfowitz told a congressional committee.

Well, we've kissed the $200-billion limit goodbye long ago. We're currently out of pocket more than $400-billion and adding to the bill at the rate of $8-billion per month. Iraq's oil riches have contributed nothing at all.

So what's the current upper-range estimate? Trillions.

According to an analysis by professor Linda Bilmes of the Kennedy School at Harvard and professor Joseph Stiglitz of Columbia University, if you use government assumptions about the size of troop strength over the coming years, the war will cost us $1-trillion in direct budgetary outlays. Then, they say, add another trillion dollars for the war's adverse impact on our economy, such things as the loss of economic services by the men and women disabled during the war, the increase in the price of oil and other macroeconomic factors.

Bilmes says that most people have trouble understanding the scale of $2-trillion. To grasp the number, she says, one should think of it like this: "1-billion seconds equals 32 years; 1-trillion seconds equals 300 centuries."

Just add this to the list of reasons why Iraq has been an unmitigated disaster. As our intelligence agencies' made crystal clear, far from making us safer the war has incubated and expanded Islamic terrorism. Rather than freedom on the march in Iraq, the war has incited a gruesome sectarian civil war.

Our nation has lost more than 2,600 fighting men and women with many times that devastatingly injured. And just wait until the huge cost of the war sucker-punches us - the bill has not yet come due, but President Bush put it all on our tab.

We have deployed 1.3-million troops to the Iraq and Afghanistan theaters, largely to Iraq, and of those nearly 600,000 are now veterans. Already, more than 184,000 have already received care from the Veterans Administration. Obviously it is a national obligation to care for these veterans, but just take a gander at the staggering amount it will cost.

Here is what Bilmes and Stiglitz found:

Due to advances in body armor, survival rates for soldiers have increased dramatically. But the darker side of this blessing are the traumatic head and brain injuries that leave many completely dependent on caregivers. This group now makes up about 20 percent of the injured, and the estimated cost of providing continual lifetime care for them is $35-billion. That's on top of the estimate that additional VA costs for returning veterans from Iraq will run $57-billion.

These veterans may also be eligible to claim disability benefits of up to $44,000 annually. Bilmes and Stiglitz have used figures from the first Gulf War to project what we can expect from this one. For a war that lasted four weeks and tallied fewer than 500 wounded in action, 169,000 veterans are being paid on average nearly $12,000 per year in disability claims. More than a third of those deployed filed claims. If the same holds true for the current conflict in Iraq (and how could it not as the war stretches well into its fourth year), the researchers estimate it will cost $122-billion to fulfill this obligation.

From the start the Bush administration has tried to cover up the outlandish expenses associated with going into Iraq. Initially, by refusing to provide figures at all, then lowballing the estimates and then paying for it through more than a dozen "emergency supplemental" requests rather than putting predictable outlays in the budget.

The burdensome cost of this war is a tangible danger to the future security of our nation, not one conjured through ginned-up intelligence. Iraq is Bush's folly and Bush's shame, but we're the ones who will pay.